310 



WHEELER— ANT LARV^. 



little fat tissue, but their hypodermis is much thickened and consists 

 of crowded cells arranged in peculiar clusters. In section the ab- 

 dominal appendages appear as in Fig. lo. The fusiform base is 

 filled with large, clear trophocytes, or fat-cells, some of which in the 

 middle of the swelling may contain urate crystals, like those in the 

 prothoracic storage kidney, but the slender, tubular distal portion 

 contains a granular liquid, which can only be regarded as an exudate 



d 



Fig. 10. Longitudinal section througli exudatorium of first abdominal segment 

 of trophidium of Pachysima latifrons Emery. 



derived from the trophocytes in the basal enlargement. This exu- 

 date is evidently filtered through the thin cuticula covering the ap- 

 pendage by pressure, for there is a rather elaborate system of 

 muscles, as in the ccthiops larva, surrounding the bases of the appen- 

 dages and capable of subjecting their contents to pressure. The 

 head is small and has soft, blunt, rudimentary and unchitinized man- 

 dibles, and the labium bears a pair of long, palp-like appendages, 

 which project forward in the deep depression between the head and 

 the swollen sternal portion of the first abdominal segment. These 

 are probably also exudatoria and seem roughly to correspond to the 

 unpaired tentacle of the ccthiops larva. The structure of the mouth- 

 parts shows that the larva in this stage is fed with liquid food re- 

 gurgitated by the workers. The convex dorsal surface is beset with 

 sparse, curved bristles of uniform thickness, with blunt tips. The 

 segmentation of the body is indistinct and its posterior end curves 

 forward and terminates in a large tubercle with the anal orifice just 

 anterior to its base. Fig. gB, drawn from a stained and cleared 



